P1256: IMPACT OF CRYOPRESERVATION OF PERIPHERAL BLOOD STEM CELLS FOR ALLOGENIC HEMATOPOIETIC STEM CELL TRANSPLANTATION ON HEMATOPOIETIC RECONSTITUTION: A SINGLE-CENTER EXPERIENCE.
Authors: Esther Maria Ortega Vida, Lourdes Dominguez Acosta, Mario García Fletes
Journal: HemaSphere (2023)

Topic: 21. Stem cell transplantation - Experimental Background: The COVID-19 pandemic has implemented cryopreservation of peripheral blood stem cells (PBSC) for allogenic hematopoietic stem cell transplantation (allo-HSCT) in order to ensure the viability of transplant procedures. The risk of SARS-CoV-2 infection of donors during stem cell mobilization and collection, quarantines and travel restrictions had severely affected our ability to infuse fresh donor cells. While some studies found no significant impact of graft manipulation on patient outcome, others found association with delayed engraftment. Aims: We evaluate outcomes of HCT using cryopreserved versus fresh grafts in patients undergoing HCT for hematologic malignancy. Methods: A total of 112 patients were included in the analysis. In this study we compare 61 patients who underwent allo-HSCT from cryopreserved PBSC (Cryopreserved Group) during de COVID-19 pandemic (since March 2020) with 51 patients who underwent allo-HSCT from fresh PBSC (Fresh Group) in the previous period (between 2018 and 2020). Recipients of cryopreserved graft were divided into 3 cohorts based on graft source: HLA-matched related PBSC donors (n = 25), matched unrelated PBSC donors (n = 27), and haploidentical PBSC donors (n = 9) compare with recipients of fresh graft: HLA-matched related PBSC donors (n = 23), matched unrelated PBSC donors (n = 15), and haploidentical PBSC donors (n = 13). The primary endpoint was engraftment. Results: Median neutrophil engraftment was 16.7 and 16.2 days with cryopreserved and fresh grafts, respectively (P=.091). Non-significant delays were found in platelet recovery days (16.8 versus 16; P =.673). However, multivariate analyses showed a significant delay in platelets engraftment with haploidentical donors more than HLA-matched and unrelated (P < 0.001) in both groups (Cryopreserved group and Fresh group). There was no delay in engraftment between the cryopreserved and fresh graft according to the type of donor (HLA-matched (HR, 1.08; 95% CI, 0.61 to 1.93; P=.519); unrelated donor (HR, 1.20; 95% CI, 0.60 to 2.41; P=.591); haploidentical donor (HR, 1.38; 95% CI, 0.35 to 3.59; P=.507) Summary/Conclusion: This analysis reports our experience during the COVID-19 pandemic with cryopreservation of peripheral blood stem cells (PBSC) for allogenic hematopoietic stem cell transplantation. We conclude that cryopreservation of peripheral blood stem cells (PBSC) is not associated with statistically significant delays in engraftment. There was no delay in engraftment even according to the type of donor (HLA-matched, unrelated donor or haploidentical donor). However, we noticed a significant delay in platelets engraftment with haploidentical donors more than HLA-matched and unrelated, independently of cryopreservation. We consider that cryopreservation is a safe alternative to maintain transplant procedures despite all the difficulties and obstacles we faced since the beginning of the pandemic..Keywords: Engraftment, Cryopreservation, COVID-19, Allogeneic hematopoietic stem cell transplant